SPORE GERMINATION OF ARBUSCULAR MYCORRHIZAL FUNGI IN SOILS DIFFERING IN HEAVY-METAL CONTENT AND OTHER PARAMETERS

A simple sandwich device was used to study the spore germination of a Cd-tolerant arbuscular mycorrhizal fungus (Glomus mosseae P2) isolated from a metal polluted soil and a Cd-sensitive one (Glomus mosseae Gm) in a range of agricultural soils differing in metal content and other parameters. The percentage of spore germination varied between the so ils from 0 to the level of the sand+water control. There was no correl ation between percentage germination of either P2 or Gm spores and the Ca(NO3)(2)-extractable Cd concentration of the soils. Spore germinati on was positively correlated with soil pH, particularly for the P2 iso late. In soils from a sewage sludge trial the depression of spore germ ination was also correlated with high concentrations of available P. T he irradiation and reinoculation of P2 soil with the autochtonous micr oflora did not significantly affect germination of P2 or Gm spores. Th ese results show that edaphic factors other than heavy metal content p redominently influence germination of AM fungi in these soils. The use of the test device the selection of tolerant strains and as a routine method for biomonitoring soil metal pollution or other soil disturban ce is discussed.